How do i lose weight!? im goin crazy here!?

I exercise like crazy and dont eat very much but yet i can only maintain my weight. i use to bike 20 miles every day and still would not lose weight, ive tried calorie counting and such, but it always seems ineffective, i dont look for the quick and easy answer either, i know that losing is hard work. what is the barebones thing that I need to do? is it diet? i hear some people say its 90 percent diet and 10 percent exercise. help! also eating 5 meals throughout the day is almost impossible for me, i work very late at a restraunt (and dont eat the food there) i get home at about 1 am and have to wake up at 7 the next day to go to school, its extremely hard to fit in 5 meals throughout such a busy day. any advice will be appreciated and considered :) thank you!